Over the past few decades, a primary focus has been on the negative health effects of not participating in regular moderate-to-vigorous physical activity (MPVA). Only recently has sedentary behavior been studied as a distinct and independent risk factor for adverse health outcomes. This dissertation sought to provide new insights into sedentary behavior in desk-dependent office workers.
The purpose of the first study was to assess correlates of sedentary behavior in office workers. Cross-sectional analysis of data from the Recharge@Work Study was used to assess behavioral, social, and organizational correlates of objectively measured sedentary time in desk-dependent office workers at two hospitals located in the Portland-Vancouver metropolitan area. Respondents were recruited from desk-dependent administration hospital workers. Analysis included 70 adults (~49.2 years old), with three behavioral, three social and one organizational variable assessed by, computerized questionnaires. Sedentary activity assessed by accelerometry and expressed as prolonged sedentary bouts (60 minute blocks ≤ 150 counts per minute [cpm]). No significant associations were found between age, gender, BMI, outcome expectancy, or self-efficacy and sedentary behavior. In individuals with low perceived senior management support, direct supervisor support and enjoyment were strongly associated with prolonged sedentary behavior (OR=13.6, OR=16.3 respectively). Individuals with high perceived senior management support showed no association between enjoyment and management support and sedentary behavior. In individuals with low direct supervisor support, enjoyment was significantly associated with prolonged sedentary behavior (OR=12.2), but not associated with individuals with high direct supervisor support. The results from this study suggest manager support and enjoyment may be important targets for developing effective intervention strategies to reduce sedentary behavior in office workers.
The purpose of the second study was to assess the efficacy of a theory-based behavior intervention to incorporate active breaks into the workday of office workers. Desk-dependent office workers exhibit high levels of prolonged sedentary behavior, and theory-based interventions to break up sedentary time within this population are needed. The study examined the effectiveness of Recharge@Work: a 12-week, theory-based intervention to decrease overall sedentary time and prolonged (>60min) sedentary time during the workday in desk-dependent hospital administrative staff. Two hospitals were matched with one serving as the comparison site (N=26) and the other serving as the intervention site (N=39). The intervention consisted of personalized feedback on sedentary behavior and individual toolkits. Toolkits included items to improve self-regulation in taking short 2-3 minute active breaks every 60 minutes (timers, activity log, activity examples). Data were collected at baseline, mid-intervention (6wk) and end-intervention (12wk). Relative to the comparison group, the intervention group significantly reduced the percent of workday spent in sedentary time (p<.001; partial eta-square=.09) and the percent of workday spent in prolonged (>60min) sedentary bouts (p<.001; partial-eta square=.12). No changes in mediating variables were observed between the two groups. This study provides support for the short-term effectiveness of a multicomponent intervention to support active breaks in desk-dependent office workers.